Heat dissipating fans are often used to cooperate with heat sinks to dissipating heat from heat source such as CPUs (Center Processing Units) in computer systems. In such a heat dissipating fan, a stator has stator coils to generate alternating electromagnetic fields when charged with alternating current, and a rotor comprises a blade set and a permanent magnet carried by the blade set. The permanent magnetic field of the permanent magnet interacts with the electromagnetic fields of the stator coils to drive the blade set to rotate, thereby generating airflow toward components to be cooled. To rotatably support the blade set, the heat dissipating fan usually comprises a bearing, and the rotor comprises a rotary shaft extending from the blade set into the bearing.
For the computer systems, especially for portable computer systems such as, for example, notebook computers, there exists a trend toward miniaturized size in the relevant industry. In particular, the portable computer systems are desired to have a low profile, i.e., a small thickness, to make them more appealing to customers. Therefore, it may be desirable to provide a heat dissipating fan having a reduced axial size.
As the axial size of the heat dissipating fan is reduced, the axial height of the bearing is reduced accordingly. However, as the height of the bearing is reduced, the supporting area between the bearing and the rotary shaft is reduced accordingly. This may cause vibration of the blade set during rotation thereof and unwanted noise thereby. Therefore, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies.